Valve and dispenser using the valve

ABSTRACT

A valve for a pneumatic dispenser, the dispenser comprising a handle with an actuation arrangement for selectively applying pressure to a respective one of the front and rear chambers on either side of a piston coupled to a rod for applying a dispensing force, thereby controlling movement of the rod. The valve is provided with a body and first and second moveable members moveable relative to the body. The valve can be arranged as a space saving five port valve instead of two three port valves for use in the disclosed dispenser and can be arranged to provide a fail safe mechanism if both valve members are actuated concurrently. A dispenser comprising a stock portion and a cylinder secured to the stock portion is disclosed. Pressure is supplied to the rear chamber of the cylinder from the stock portion through its front chamber and the piston moveable inside the cylinder.

RELATED APPLICATION

The present application claims priority to EP Application No. 10196810.5filed Dec. 23, 2010, which is incorporated herein in its entirety byreference.

FIELD OF THE INVENTION

The present invention relates to a valve, particularly although notexclusively, a five port valve. The valve finds application in apneumatic dispenser, particularly but not exclusively, for applying aforce to a container holding viscous material to cause the viscousmaterial to be dispensed from the container.

SUMMARY

European Patent Application EP0551998 A1 discloses a dispenser forviscous material. The dispenser comprises an actuating cylindercontaining a piston connected to a rod which extends forward out of thecylinder, and a pistol grip body, in which is mounted a trigger operablyconnected with a pressure regulator. Actuation of the trigger causes apressure to be applied to the cylinder via a flexible pipe extendingfrom a regulated two port valve inside the pistol grip to the rear endof the cylinder. The applied pressure causes the piston and, hence, therod to move forward. A keep is located forward of the cylinder. The keepenables a removable cartridge to be inserted such that application of aforce by the rod to a piston inside the cartridge causes viscousmaterial to be dispensed from the cartridge through an aperture. Aswitch located at an end of the pistol grip distal to the cylinder isused to select between different outlets leading to opposite sides ofthe piston to enable the piston to be pneumatically driven in either theforward or the rearward direction, according to the selection of theswitch. In either case, the pressure is vented from the cylinder afterthe trigger is released by a dump valve at the rear of the cylinder.When pressure is applied on actuation of the trigger, the dump valvecloses until the applied pressure drops when the trigger is released andthe dump valve opens to act as a rapid exhaust.

Dispensers of a similar general construction as disclosed in EP0551998A1 are known, which also have a flexible pipe extending from the pistolgrip to the rear of the cylinder but have a button at the rear of thecylinder that allows the operator to control whether the pressureapplied through the flexible pipe from the pistol grip is applieddirectly to the rear portion of the cylinder on one side of the piston,or through a coiled tube and the piston to the front portion of thecylinder on the other side of the piston. As for EP0551998, a pressureactivated dump valve is used to vent the cylinder to atmosphere when thetrigger is released.

A common feature of these dispensers is that, in order to change thedirection of movement of the piston, the operator must either use twohands or at least move the hand holding the pistol grip from its normalposition with the index finger of this hand on the trigger. This causesdelays in the operation of the dispenser while the operator moves hishand(s) in order to make the necessary adjustments to the dispenser.Another common feature of these dispensers is that a flexible pipeextends from the pistol grip to the rear end of the cylinder. Thisflexible pipe hangs loosely from the cylinder and can be a safetyhazard. It is also prone to damage and can detract from the visualappearance of the dispenser. The operation of the dump valve to vent thecylinder can involve high levels of noise.

U.S. Pat. No. 2,692,706 discloses an air pressure caulking gun with apair of longitudinally spaced apart air control valves in a valve blockactuated by a pivotally mounted trigger member. A trigger finger sits ona valve seat of each control valve to regulate a flow of compressed airto the ports that supply or exhaust air from the valve ports.

One aspect of the invention provides a dispenser comprising a handle. Acylinder is secured with respect to the handle. A piston is moveableinside the cylinder, the piston dividing the cylinder into a frontchamber and a rear chamber. A rod is arranged to move with the piston,the rod extending from the piston through an aperture in a front end ofthe cylinder. The handle houses a valve, comprising a body and first andsecond moveable members linked to an actuation arrangement forcontrolling the advance and retreat of the rod by actuation of arespective one of the first and second members. The body defines a valvechamber and first, second, third, fourth and fifth ports into the valvechamber, the second and fourth ports being connected to, respectively,the rear and front chamber. The first and second members are moveablewithin the valve chamber to selectively open and close fluidiccommunication paths between the ports. The first member is movablebetween two positions to selectively enable fluidic communicationbetween the second port and either the first port or the third port. Thesecond member is movable between two positions to selectively enablefluidic communication between the fourth port and either the third portor the fifth port.

Advantageously, a dispenser with a compact five-port valve can beconstructed, in effect combining two three port valves in a single valvebody by sharing one of the ports of each notional three port valve. Insome embodiments, the second and fourth ports are connected as operatingports (for example to either side of the piston in a dispenser asdescribed above), one of the first, third and fifth ports beingconnected as a supply or exhaust port and the other two being connectedas the exhaust or supply ports, respectively. Space savings are achievedby allowing the operating ports to share a common exhaust or inlet port.A fail-safe may be provided by preventing substantial pressure build-upat both operating ports at the same time.

In some embodiments, the first and second members are constrained tomove along the same axis and the first and second members may be biasedaway from each other into respective rest positions. A resilient biasingmember may be disposed between the first and second members to this end.In some embodiments, the members are dimensioned such that the possibletravel of each of the members is determined by the position of the otherone of the members, for example, the members can be arranged to contacteach other if one of the members is fully inserted into the chamber. Themembers may be arranged to be capable of contacting each other insidethe chamber to limit how much both members can be inserted at the sametime.

In some embodiments the first, third and fifth ports are in fluidiccommunication in configurations of the first and second members withboth the first and second members positioned away from their respectiverest positions. Where the second and fourth ports are connected asoperating ports, it is thus ensured that pressure applied via one ormore of the first, third and fifth ports is vented through another oneor more of these ports, which are connected as exhaust ports, if bothmembers are actuated at the same time.

In some embodiments, for example with the first and fifth port connectedto supply pressure to the second and fourth port connected as operatingports and the third port connected as an exhaust port, when the firstand second members are in their respective rest positions, fluidiccommunication is enabled between the second port and the third port, andbetween the third port and the fourth port, and fluidic communication isprevented between the first port and the second port, and between thefourth port and the fifth port; when the first member is positioned asclosely as possible to the second member while the second member remainsin its rest position, fluidic communication is enabled between thesecond port and the third port, and between the fourth port and thefifth port, and fluidic communication is prevented between the firstport and the second port, and between the third port and the fourthport; when the second member is positioned as closely as possible to thefirst member while the first member remains in its rest position,fluidic communication is enabled between the first port and the secondport, and between the third port and the fourth port, and fluidiccommunication is prevented between the second port and the third port,and between the fourth port and the fifth port. There is noconfiguration in this embodiment of the first and second members inwhich fluidic communication is enabled between the first port and thesecond port, and between the fourth port and the fifth port, without atleast one of the second port and the fourth port also being in fluidiccommunication with the third port.

In some embodiments, for example with the first and fifth port connectedas exhaust ports for the second and fourth port connected as operatingports and the third port connected to supply pressure, when the firstand second members are in their respective rest positions, fluidiccommunication is enabled between the first port and the second port, andbetween the fourth port and the fifth port, and fluidic communication isprevented between the second port and the third port, and between thethird port and the fourth port; when the first member is positioned asclosely as possible to the second member while the second member remainsin its rest position, fluidic communication is enabled between the firstport and the second port, and between the third port and the fourthport, and fluidic communication is prevented between the second port andthe third port, and between the fourth port and the fifth port; when thesecond member is positioned as closely as possible to the first memberwhile the first member remains in its rest position, fluidiccommunication is enabled between the second port and the third port, andbetween the fourth port and the fifth port, and fluidic communication isprevented between the first port and the second port, and between thethird port and the fourth port. In this embodiment there is noconfiguration of the first and second members in which fluidiccommunication is enabled between the second port and the third port, andbetween the third port and the fourth port, without the first port beingin fluidic communication with the second port and/or the fourth portbeing in fluidic communication with the fifth port.

In some embodiments, the first and fifth port are connected to apressure supply arrangement and the third port is connected to anexhaust arrangement, saving space in particular if the exhaustarrangement comprises a silencer. In some embodiments, the pressuresupply arrangement comprises a respective pressure regulator for each ofthe first and fifth ports, allowing the pressure to be adapted for eachchamber, for example using a lower pressure to retreat the rod, therebysaving air when less force is needed. In some embodiments, the rodextends from the piston through the front space. A first fluid conduitis provided for enabling a pressure to be applied from the stock portionto the rear space to advance the rod. The first fluid conduit passesthrough the front space. This enables the rod to be driven forwardwithout the need for a tube external to the cylinder between the handleand the cylinder.

Advantageously, the stock portion and the cylinder can together fullyenclose the first fluid conduit. The valve arrangement and the cylinderare then arranged to be in fluidic communication entirely through fluidpaths contained within the dispenser, i.e. through the handle andpassing directly into the cylinder without first leaving the handle.This ensures that the dispenser is compact, and provides a simpler formfactor of the dispenser due to the absence of any visible external fluidpaths. The dispenser is also safer as all fluid paths are containedwithin the dispenser and not exposed, and therefore are less liable tobe damaged.

In some embodiments, the first conduit passes through an aperture in thepiston so that the piston slides along the conduit. In some embodiments,the dispenser further comprises a second fluid conduit passing from thestock portion to the front space for enabling a pressure to be appliedto the front space to retreat the rod, the second fluid conduit passingdirectly from the stock portion to the front space. In some embodiments,the stock portion and the cylinder fully enclose the first and secondfluid conduits. An actuation arrangement may be provided to control theapplication of pressure via the first and second conduits to advance andretreat the rod.

Any of the dispensers described above may comprise a holder for holdinga container, such as a cartridge or foil pack, containing viscousmaterial to enable application of a dispensing force to the container asthe rod advances, thereby dispensing at least some of the viscousmaterial from the container.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are now described by way of example onlyand with reference to the accompanying drawings, in which:

FIG. 1 depicts a perspective view of a dispenser;

FIG. 2 depicts a cross-section of part of the dispenser;

FIG. 3 depicts a valve arrangement and associated components;

FIG. 4A depicts a cross-section of the valve arrangement in a restconfiguration;

FIG. 4B depicts a cross-section of another embodiment of the valvearrangement in the rest configuration;

FIG. 5A depicts a cross-section of the valve arrangement in a driveconfiguration;

FIG. 5B depicts a cross-section of the other embodiment of the valvearrangement in the drive configuration;

FIG. 6A depicts a cross-section of the valve arrangement in a returnconfiguration;

FIG. 6B depicts a cross-section of the other embodiment of the valvearrangement in the return configuration;

FIG. 7A depicts a cross-section of the valve arrangement in aconfiguration in which each of its two spools has been depressed; and

FIG. 7B depicts a cross-section of the valve arrangement in aconfiguration in which each of its two spools has been depressed.

DETAILED DESCRIPTION

With reference to FIG. 1, a pneumatic dispenser 2 comprises a cylinder 4secured to a stock portion 6 and a cartridge holder 8 secured forward ofthe cylinder 4. The cylinder has a wall with a substantially annularcross-section. The cartridge holder 8 is arranged to receive a cartridge(not shown) containing viscous material and is arranged such that thecartridge held in the cartridge holder 8 is disposed in a dispensingrelationship relative to the cylinder 4, as described below.

The specific embodiment depicted in FIG. 1 is arranged to dispensematerial from two component cartridges having two barrels, one for eachcomponent material and has two plungers, one for each barrel. Aplurality of rods 10 extend through a front end of the cylinder 4through respective apertures, which seal around the rods 10. The rods 10extend substantially parallel to a longitudinal axis of the cylinder 4.A plunger 12 for engaging a piston inside the cartridge is coupled totwo of the rods 10 at a forward end of the rods 10. A further, smallerplunger is coupled to the remaining rod. The smaller plunger andremaining rod are obscured behind the cartridge holder 4 in FIG. 1. Therods 10 and the plungers 12 are moveable relative to the cylinder 4along a longitudinal axis of the rods 10 such that a force can beapplied to the cartridge by the plungers 12 when the cylinder 4 ispressurized to cause viscous material to be dispensed from thecartridge.

The stock portion 6 comprises a handle 14 extending away from thecylinder 4 in the vicinity of the front end of the cylinder 4. Thehandle 14 is ergonomically shaped to be held by one hand of a humanoperator of the dispenser 2 and comprises a drive trigger 18 and areturn trigger 20 for, respectively, controlling the advance and return(i.e. retreat) of the rods 10. The drive trigger 18 and the returntrigger 20 face substantially forward and are positioned on the handle14 such that each trigger can be individually depressed by the operatorwhile the operator's hand is holding the handle 14. The drive trigger 18is positioned on the handle 14 further from the cylinder 4 such that itis actuatable by the middle finger of the operator's hand, and thereturn trigger 20 is positioned on the handle 14 closer to the cylinder4 such that it is actuatable by the index finger of the operator's hand.The handle 14 also comprises a regulator 22 at an end of the handle 14distal to the cylinder 4. The regulator 22 has a quick release pressureconnector 24 arranged to connect to a pressure hose to receivepressurized fluid (for example, compressed air) from a pressure source(not shown) and a dial 26 for controlling the pressure of thepressurized fluid supplied by the regulator 22.

With reference to FIG. 2, depicting a cross-section of the dispenserwith one of the rods 10 visible, a piston 28 coupled to the rods 10 fordriving the rods 10 is slidingly accommodated within the cylinder 4. Thepiston 28 divides the inside of the cylinder 4 into two chambers: adrive chamber 30 on the rearward side of the piston 28 between thepiston 28 and a closure member 32 closing the back end of the cylinder4, and a return chamber 34 on the forward side of the piston 28 betweenthe piston 28 and the apertures around the rods 10. The rods 10 arecoupled to the piston 28 and extend forward of the piston 28. The rods10 thus move with the piston 28 relative to the cylinder 4 parallel tothe longitudinal axis of the cylinder 4.

A valve 36 is situated within the handle 14 so that it is actuatable bythe return trigger 20 and the drive trigger 18. The return trigger 20 isarranged to directly engage a first spool (described below) of the valveand the drive trigger 18 is arranged to actuate a second spool(described below) of the valve via a yoke while the drive trigger 20pivots about a pivot forward of the valve.

A return conduit 38 passes from the valve 36 through an aperture in thecylinder 4 into the return chamber 34 to enable fluidic communicationbetween the valve 36 and the return chamber 34. A drive conduit 40passing from the valve 36 to the drive chamber 30 comprises a firstdrive conduit portion 42, which passes from the valve 36 to the returnchamber 34 through a further aperture in the cylinder 4. Fluid isprevented from escaping the return chamber 34 between the respectiveapertures and the outside of the first drive conduit portion 42 or thereturn conduit 38 by a sealing member 44. The sealing member 44sealingly holds O-rings 80 in place around each of the return conduit 38and the drive conduit 40 and against an inner surface of the cylinder 4around each of the apertures. A second drive conduit portion 46 passesfrom the sealing member through the return chamber 34 and extendsthrough an aperture in the piston 28 into the drive chamber 30 to enablefluidic communication between the valve 36 and the drive chamber 30. Theaperture in the piston 28 seals around the second drive conduit portion46, and the drive conduit 40 is therefore sealed from the return chamber34. In operation, the piston 28 slides over the second drive conduitportion 46 whilst maintaining the seal around it.

The valve 36 is in fluidic communication with a pressure inlet conduit48 connected to the regulator 22. The valve 36 is also in fluidiccommunication with an exhaust 50 for releasing pressure in the cylinder4 to the atmosphere. The exhaust 50 is arranged to act as a silencer inorder to reduce the noise emitted from the dispenser 2 when the cylinder4 is vented through the exhaust 50.

The valve 36 is arranged such that the pressure inlet conduit 48 and theexhaust 50 are each selectively in fluidic communication with the drivechamber 30 and the return chamber 34 under control of the triggers.Actuation of the valve 36 using the triggers enables the operator of thedispenser 2 to selectively enable or prevent fluidic communicationbetween combinations of the pressure inlet conduit 48, the exhaust 50,the drive chamber 30 and the return chamber 34 to advance or retreat therods 10.

In use, when neither the drive trigger 18 nor the return trigger 20 hasbeen depressed by the operator, the dispenser 2 is in a restconfiguration. In the rest configuration, the regulator 22 isdisconnected from both the drive chamber 30 and the return chamber 34and both chambers are connected to the exhaust 50, placing the drivechamber 30 and the return chamber 34 at atmospheric pressure.

When the drive trigger 18 has been fully depressed by the operator, andthe return trigger 20 is not depressed, the dispenser 2 is in a driveconfiguration. In the drive configuration, the regulator 22 is connectedthe drive chamber 30 and remains disconnected from the return chamber34, which remains connected to the exhaust 50. The exhaust 50 isdisconnected from the drive chamber 30, so that pressure builds up inthe drive chamber 30, driving the piston 28 and, hence, the rods 10forward.

When the return trigger 20 has been fully depressed by the operator, andthe drive trigger 18 is not depressed, the dispenser 2 is in a returnconfiguration. In the return configuration, fluidic communicationbetween the pressure inlet conduit 48 and the return chamber 34 isenabled, and fluidic communication between the pressure inlet conduit 48and each of the drive chamber 30 and the exhaust 50 is prevented.Fluidic communication between the exhaust 50 and the drive chamber 30 isenabled, and fluidic communication between the exhaust 50 and the returnchamber 34 is prevented. In the return configuration, pressurized fluidis applied to the return chamber 34, which causes the piston 28 to moverearwards.

When each of the drive trigger 18 and the return trigger 20 aredepressed by the same amount, and each are depressed as much as they canboth be depressed at the same time, the dispenser 2 is in a free flowconfiguration. In the free flow configuration, a pressure increase inthe drive chamber 30 and/or the return chamber 34 is prevented. This isachieved by enabling fluidic communication between the drive chamber 30and the exhaust 50 and between the return chamber 34 and the exhaust 50.Fluidic communication is also enabled between the pressure inlet conduit48 and the exhaust 50.

When both triggers are depressed as far as possible, they areeffectively coupled to each other via the spools of the valve 36, asdescribed below, so that any inward movement of one trigger carriesoutward movement of the other trigger. Thus with both triggers pressed,an operator can vary between the configurations described above byvarying the force applied to each trigger. However, the valve 36 and itslink to the triggers are arranged such that, for any amount ofdepression of either or both the triggers, it is never the case that theregulator 22 is able to supply a substantial increase in pressure toboth the drive chamber 30 and the return chamber 34 at the same time.Depending on the amounts of depression of the two triggers, either thereis substantially no increase in pressure in each of the two chambers, orthere is a substantial increase in pressure in only one of the chambers.

The configurations of the dispenser 2, and in particular the valve 36are now described in more detail with reference to FIGS. 3, 4A, 5A, 6Aand 7A. The valve 36 comprises a valve body 60, which defines asubstantially cylindrical valve chamber 62. The valve body 60 defines areturn inlet port 64, a return operating port 66, an exhaust port 68, adrive operating port 70 and a drive inlet port 72, arrangedconsecutively with respect to the longitudinal axis of the valve chamber62. The pressure inlet conduit 48, which is connected to the regulator22, bifurcates between the regulator 22 and the valve 36, such that adrive inlet conduit 52 is connected to the drive inlet port 72 and areturn inlet conduit 54 is connected to the return inlet port 64. Theexhaust 50 is connected to the exhaust port 68.

A drive spool 56 and a return spool 58 are each moveable within thevalve 36 to actuate the valve 36. As shown in FIG. 2 and discussedabove, the drive trigger 18 is connected to the drive spool 56, and thereturn trigger 20 is connected to the return spool 58 by respectivemechanical links, which cause each spool to move as each respectivetrigger is depressed.

The drive spool 56 and the return spool 58 are situated in the valvechamber 62 and are moveable within the valve chamber 62 substantiallyalong the longitudinal axis of the valve chamber 62. Each spool extendsthrough a respective aperture in the valve body 60 at opposite ends ofthe valve chamber 62 along the longitudinal axis. A spring 74 issituated within the valve chamber 62 between the drive spool 56 and thereturn spool 58. The spring 74 is in compression and exerts a force onthe spools which acts to move them apart. A maximum separation distanceof the drive spool 56 and the return spool 58 is defined by a first stop76 and a second stop 78, each defined by the valve body 60, and eachacting to prevent movement of the drive spool 56 and the return spool58, respectively, beyond a maximum separation distance.

Each spool comprises lands and grooves as shown, for example, in FIG.4A. A plurality of O-rings 80 are positioned in the valve chamber 62 asshown, for example, in FIG. 4A to define adjacent regions of space alongthe valve chamber 62 between pairs of the O-rings 80. Each region ofspace contains one of the five ports. When a land of either of thespools is situated within one of the O-rings 80, fluidic communicationbetween the two regions of space on either side of that O-ring 80 isprevented, and therefore fluidic communication between the two portsassociated with the two regions of space is prevented. Given theconsecutive arrangement of the regions of space along the valve chamber62, if, for example, fluidic communication between the return inlet port64 and the return operating port 66 is prevented, fluidic communicationis also prevented between the return inlet port 64 and any of the otherports.

Each of the ports and each of the apertures through which the spoolsextend out of the valve body 60 are individually sealed by respectiveO-rings 80 to prevent fluid from escaping from or entering the valvechamber 62 other than through the valve ports.

With reference to FIG. 4A, in the rest configuration, the spools 56, 58are at their maximum separation distance, and are positioned such thatfluidic communication between the return inlet port 64 and the returnoperating port 66 is prevented, fluidic communication between the returnoperating port 66 and the exhaust port 68 is enabled, fluidiccommunication between the exhaust port 68 and the drive operating port70 is enabled, and fluidic communication between the drive operatingport 70 and the drive inlet port 72 is prevented, connecting thecylinder 4 on either side of the piston 28 to the atmosphere, so thatthe piston is not driven.

With reference to FIG. 5A, in the drive configuration, the drive spool56 has been moved by the drive trigger 18 from its position in the restconfiguration towards the return spool 58 to abut the return spool 58.The spools are positioned such that fluidic communication between thereturn inlet port 64 and the return operating port 66 is prevented,fluidic communication between the return operating port 66 and theexhaust port 68 is enabled, fluidic communication between the exhaustport 68 and the drive operating port 70 is prevented, and fluidiccommunication between the drive operating port 70 and the drive inletport 72 is enabled, connecting the drive operating port 70 to theregulator 22 to apply a drive pressure to cause the piston 28 and hencethe rods 10 to advance.

With reference to FIG. 6A, in the return configuration, the return spool58 has been moved from its position in the rest configuration towardsthe drive spool 56 to abut the drive spool 56. The spools are positionedsuch that fluidic communication between the return inlet port 64 and thereturn operating port 66 is enabled, fluidic communication between thereturn operating port 66 and the exhaust port 68 is prevented, fluidiccommunication between the exhaust port 68 and the drive operating port70 is enabled, and fluidic communication between the drive operatingport 70 and the drive inlet port 72 is prevented, connecting the returnoperating port 66 to the regulator 22 to apply a return pressure tocause the piston 28 and, hence, the rods 10 to retreat.

With reference to FIG. 7A, in the free flow configuration, the drivespool 56 and the return spool 58 have each been moved by the samedistance away from their position in the rest configuration towards eachother until the spools abut each other. The spools are positioned suchthat fluidic communication between all of the ports is enabled. As aresult, a substantial increase in pressure in the drive chamber 30and/or the return chamber 34 is prevented by enabling fluidiccommunication between the drive chamber 30, the return chamber 34, thepressure inlet conduit 48 and the exhaust 50, causing pressurized fluidfrom the regulator 22 to vent through the exhaust 50.

The above described specific embodiment is manufactured from acombination of metal for the cylinder 4, the rods 10 and the cartridgeholder 8 and plastic materials for the remaining structural componentsincluding the stock portion 6. The cylinder 4 and end plates at thedistal end of the cartridge holder 8 are made of aluminium, and the rods10 and the remainder of the cartridge holder 8 are made of steel. Theplastic materials used are nylon or acetal, with glass fillers whererequired. It will be understood that any suitable combination of thesematerials, including construction with all structural parts made fromplastic materials can be used in alternative embodiments. Numerousmaterials are suitable for use in the sealing parts such as O-rings, forpressure connecting hoses and tubes and other pneumatic components suchas valves and connectors, as is well known to the person skilled in theart.

It will be understood that the above description of specific embodimentsof the invention is by way of example only and it is not intended tolimit the scope of the invention. Many modifications of the describedembodiments, some of which are now described, are envisaged and intendedto be covered by the appended claims.

While the specific embodiment described above has a valve connected withone exhaust port 68 and two inlet ports 64, 72, some embodiments havetwo exhaust ports and a single inlet port. With reference to FIGS. 4B,5B, 6B and 7B, a dual exhaust embodiment is similar to the embodimentdescribed above, with the main differences between the embodiments beingthat the dispenser 2 comprises a drive exhaust 82 arranged to relievepressure from the drive chamber 30 and a return exhaust 84 arranged torelieve pressure from the return chamber 34, and that the pressure inletconduit does not bifurcate, but has a common pressure inlet conduit 86connected to one port of the valve 36, selectively in fluidiccommunication with the drive chamber 30 and the return chamber 34 viathe drive conduit 40 and the return conduit 38, respectively. The landsand grooves of the spools are arranged differently from the specificembodiment described above, as shown, for example, in FIG. 4B, as aconsequence of the different roles of the ports from one end of thevalve 36 to the other.

The connections of the return operating port 66 and the drive operatingport 70 are the same as in the embodiment described above, but thereturn exhaust 84 is connected to the return inlet port 64, which nowacts as a return exhaust port, the common pressure inlet conduit 86 isconnected to the exhaust port 68, which now acts as a common inlet port,and the drive exhaust 82 is connected to the drive inlet port 72, whichnow acts as a drive exhaust port.

As can be seen from FIGS. 4B, 5B, 6B and 7B, the spools are arrangedsuch that the drive and return ports are connected to their respectiveexhaust ports in the rest configuration, the drive port is connected tothe common inlet and disconnected from its exhaust port in the driveconfiguration, and analogously for the return port in the returnconfiguration. As for the specific embodiment described above, all portsare connected in the free flow configuration.

In the free flow configuration, in some embodiments, the fluidiccommunication relationships between the ports are the same as thefluidic communication relationships described above for the restconfiguration, e.g., for the specific embodiment described above withrespect to FIG. 4A, fluidic communication between the return inlet port64 and the return operating port 66 is prevented, and fluidiccommunication between the drive operating port 70 and the drive inletport 72 is prevented.

In some embodiments, the drive spool 56 and the return spool 58 arebiased apart by any kind of biasing means such as a resilient polymericmember. The resilient biasing need not be provided between the twospools but each could have its own resilient biasing member associatedwith it, for example between the spool and the valve housing. The valvehas a different number of ports, in some embodiments, and in particular,in some embodiments, the valve has at least six ports, such that thedrive conduit and the return conduit are each selectively in fluidiccommunication with their own dedicated inlet and exhaust.

In general, while the above description has been made in terms of a fiveport valve used in a dispenser, it will be understood that the inventionis not limited in this way and extends to the valve as such,irrespective of its application. The valve will find useful applicationin many areas where it would be advantageous to combine thefunctionality of two three port valves in a single valve body, forexample to save space, by sharing one of the ports of each notionalthree port valve. Such applications include, but are not limited to,applications where pressure needs to be applied to and vented from twoseparate chambers, whether the pressure is supplied from a commonpressure source or from one respective pressure source for each chamber.Likewise, depending on the application, the ports of the valve may beplaced differently about the longitudinal axis of the valve, for exampleall to one side or at different angles about the axis.

Turning now to the above description of a dispenser incorporating such avalve, while the specific embodiment described above is adapted for usewith cartridges, in some embodiments, instead of the cartridge holder 8as described above, the dispenser 2 comprises other kinds of holders,such as a holder to allow viscous material to be dispensed from a foilpack.

In some embodiments, the drive trigger 18 and the return trigger 20 arearranged the other way around, such that actuation of the trigger closerto the cylinder 4 causes the rods 10 to advance, and actuation of thetrigger further from the cylinder 4 causes the rods 10 to retreat. Insome embodiments, this is achieved by altering the mechanical linksbetween the triggers and the valve 36, while in other embodiments, thisis achieved by connecting the second drive conduit portion 46 to theconduit portion that is in fluidic communication with the returnoperating port 66 of the valve 36 (which then acts as a drive port),rather than the drive operating port 70 of the valve 36 (which then actsas a return port).

In some embodiments, the handle 14 comprises a seesaw switch having afirst actuation surface on one side of the pivot, and a second actuationsurface on the other side of the pivot, wherein depression of onesurface causes the rods 10 to advance, and depression of the othersurface causes the rods 10 to retreat.

While the wall of the cylinder 4 of the specific embodiment describedabove has an annular cross-section, in some embodiments, the cylinder 4has a different cross-section, for example a non-annular cross-section,such as those defining a chamber of an ellipsoid or a polygonal (roundedor not) cross-section.

In some embodiments, the dispenser 2 comprises a drive regulator and areturn regulator, for regulating the supply of pressurized fluid to thedrive chamber 30 and the return chamber 34, respectively in the respectdrive and return configurations, rather than a single regulator. Thedrive regulator is in fluidic communication with a port of the valve 36via a drive inlet conduit, and the return regulator is in fluidiccommunication with another port of the valve 36 via a return inletconduit. In some of these embodiments, the regulator is arranged suchthat the pressure applied to the drive chamber 30 in the driveconfiguration is higher than the pressure applied to the return chamber34 in the return configuration. In some further ones of theseembodiments, each regulator has its own dial for changing the amount ofpressure applied to the respective chamber.

In some further embodiments, the drive conduit 40 comprises a flexible(e.g. coiled) tube attached to an aperture in the piston 28 instead ofthe second drive conduit portion 46 extending through an aperture in thepiston 28 as described with reference to FIG. 2. The flexibility of thetube allows the connection with the piston 28 to remain in place as thepiston 28 moves relative to the cylinder 4.

The above description of a specific embodiment of a dispenser above hasbeen made in terms of a dispenser for two component cartridges havingthree rods and two plungers. It will be appreciated that the number andconfiguration of the rods are central to the description of theinvention and that many other arrangements are possible within the scopeof the invention, depending on the application at hand. For example, tworods and respective identical plungers arranged symmetrically about acentral plane of the dispenser could be used for a two-componentdispenser dispensing material in equal dispensing ratios or a single rodand plunger, for example arranged along a central axis of the cylinder4, could be used for dispensing from single component, single barrelcartridges.

1. A dispenser comprising: a handle housing a valve; a cylinder securedwith respect to the handle; a piston moveable inside the cylinder, thepiston dividing the cylinder into a front chamber and a rear chamber;and a rod arranged to move with the piston, the rod extending from thepiston through an aperture in a front end of the cylinder, wherein thevalve comprises a body and first and second moveable members linked toan actuation arrangement for controlling advance and retreat of the rodby actuation of a respective one of the first and second members, thebody defining a valve chamber and first, second, third, fourth and fifthports into the valve chamber, the second and fourth ports beingconnected to, respectively, the rear and front chamber and the first andsecond members being moveable within the valve chamber to selectivelyopen and close fluidic communication paths between the ports, the firstmember being movable between two positions to selectively enable fluidiccommunication between the second port and either the first port or thethird port, the second member being movable between two positions toselectively enable fluidic communication between the fourth port andeither the third port or the fifth port, and wherein the first andsecond members are constrained to move along the same axis.
 2. Thedispenser of claim 1 wherein the ports are spaced relative to each otheralong the axis.
 3. The dispenser of claim 1 wherein the first and secondmembers are biased away from each other into respective rest positions.4. The dispenser of claim 3 wherein a resilient biasing member isdisposed between the first and second members.
 5. The dispenser of claim3 wherein the members are dimensioned such that the possible travel ofeach of the members is determined by the position of the other one ofthe members.
 6. The dispenser of claim 5 wherein the members arearranged to contact each other if one of the members is fully insertedinto the chamber.
 7. The dispenser of claim 3 wherein the first, thirdand fifth ports are in fluidic communication in configurations of thefirst and second members with both the first and second memberspositioned away from their respective rest positions.
 8. The dispenserof claim 3 wherein when the first and second members are in theirrespective rest positions, fluidic communication is enabled between thesecond port and the third port, and between the third port and thefourth port, and fluidic communication is prevented between the firstport and the second port, and between the fourth port and the fifthport; when the first member is positioned as closely as possible to thesecond member while the second member remains in its rest position,fluidic communication is enabled between the second port and the thirdport, and between the fourth port and the fifth port, and fluidiccommunication is prevented between the first port and the second port,and between the third port and the fourth port; when the second memberis positioned as closely as possible to the first member while the firstmember remains in its rest position, fluidic communication is enabledbetween the first port and the second port, and between the third portand the fourth port, and fluidic communication is prevented between thesecond port and the third port, and between the fourth port and thefifth port; and wherein there is no configuration of the first andsecond members wherein fluidic communication is enabled between thefirst port and the second port, and between the fourth port and thefifth port, without at least one of the second port and the fourth portalso being in fluidic communication with the third port.
 9. Thedispenser of claim 3 wherein when the first and second members are intheir respective rest positions, fluidic communication is enabledbetween the first port and the second port, and between the fourth portand the fifth port, and fluidic communication is prevented between thesecond port and the third port, and between the third port and thefourth port; when the first member is positioned as closely as possibleto the second member while the second member remains in its restposition, fluidic communication is enabled between the first port andthe second port, and between the third port and the fourth port, andfluidic communication is prevented between the second port and the thirdport, and between the fourth port and the fifth port; when the secondmember is positioned as closely as possible to the first member whilethe first member remains in its rest position, fluidic communication isenabled between the second port and the third port, and between thefourth port and the fifth port, and fluidic communication is preventedbetween the first port and the second port, and between the third portand the fourth port; and wherein there is no configuration of the firstand second members wherein fluidic communication is enabled between thesecond port and the third port, and between the third port and thefourth port, without the first port being in fluidic communication withthe second port and/or the fourth port being in fluidic communicationwith the fifth port.
 10. The dispenser of claim 1 wherein the first portand the fifth port are connected to a pressure supply arrangement andthe third port is connected to an exhaust arrangement.
 11. The dispenserof claim 10 wherein the exhaust arrangement comprises a silencer. 12.The dispenser of claim 10 wherein the pressure supply arrangementcomprises a respective pressure regulator for each of the first andfifth ports.
 13. The dispenser of claim 1 further comprising a holderfor holding a container containing viscous material to enableapplication of a dispensing force to the container as the rod advances,to dispense at least some of the viscous material from the container.